title: IFT88 plays a cilia- and PCP-independent role in controlling oriented cell divisions during vertebrate embryonic development.
abstract: The role for cilia in establishing planar cell polarity (PCP) is contentious. Although knockdown of genes known to function in ciliogenesis has been reported to cause PCP-related morphogenesis defects in zebrafish, genetic mutations affecting intraflagellar transport (IFT) do not show PCP phenotypes despite the requirement for IFT in cilia formation. This discrepancy has been attributed to off-target effects of antisense morpholino oligonucleotide (MO) injection, confounding maternal effects in zygotic mutant embryos, or an inability to distinguish between cilia-dependent versus cilia-independent protein functions. To determine the role of cilia in PCP, we generated maternal + zygotic IFT88 (MZift88) mutant zebrafish embryos, which never form cilia. We clearly demonstrate that cilia are not required to establish PCP. Rather, IFT88 plays a cilia-independent role in controlling oriented cell divisions at gastrulation and neurulation. Our results have important implications for the interpretation of cilia gene function in normal development and in disease.
authors.affiliation: Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada.
authors.forename: Antonia
authors.initials: A
authors.lastname: Borovina
authors.forename: Brian
authors.initials: B
authors.lastname: Ciruna
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000502:physiology*; D000818:Animals; D030801:Animals, Genetically Modified; D002455:Cell Division / Q000502:physiology; D016764:Cell Polarity / Q000502:physiology; D002923:Cilia / Q000502:physiology*; D047108:Embryonic Development / Q000502:physiology*; D005260:Female; D008297:Male; D015027:Zebrafish / Q000196:embryology*; D029961:Zebrafish Proteins / Q000502:physiology*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D029961:Zebrafish Proteins